[LAU] Ardour: UI bar with record button/clock, etc is gone

Hello, (Sorry for crossposting from Ardour list but I figured someone here could answer faster). I clicked on 'something' in Ardour 3.5.358 top bar and now it's gone. It was hiding behind the main window, so I clicked on the small up arrow on the right of the stand-alone bar (eg. detached window for these controls) and now, it's really gone from sight. I've browser the menu options but did not find where to re-activate it. Cannot record, sicne the record button is part of the bar. I have loaded the Axiom 25 control interface, but the record button of the Axiom does not enable recording (play and rewind works). How to make the top control bar visible again ? Thanks !